More of the tens of thousands of Northern California residents who fled a deadly wildfire were awaiting permission to return to their homes on Wednesday as firefighters gained more control of the sixth most destructive blaze in state history.
Calm winds were expected on Wednesday in the Carr Fire area, about 150 miles (240 km) north of Sacramento, the National Weather Service said. Temperatures above  37 C and low humidity were to likely to persist.
The fire has killed six people, including two firefighters, since gale-force winds whipped it into a flaming cyclone that jumped a river and roared with little warning into Redding and adjacent communities in the scenic Shasta-Trinity region on the night of July 26.
Four people were listed as missing in the fire zone after 16 people considered missing turned up safe, a Redding police official said.
"The weather has really been working with us," said Jude Olivas, a spokesman for the interagency firefighting team. "Right now it's very smoky. It's kind of like a lid over the fire, which keeps the activity down, which is a good thing. It gives us time to catch up."
More than a thousand homes and more than 400 businesses and other buildings were reduced to ruins as the blaze is now ranked as the sixth most destructive wildfire in California history, according to the California Department of Forestry and Fire Protection, known as Cal Fire. Another 2,500 buildings still are threatened by the flames.
Diminished winds on Tuesday helped some 4,100 firefighters gain significant ground on the fire. They had cut containment lines around 35 percent of the fire's perimeter by Wednesday morning, up from 5% during much of the past week, even as the footprint of scorched landscape grew to about 469 square kilometres, an area larger than Detroit.
The conditions allowed some evacuees to return home but as many as 37,000 remained displaced.
Lighter winds also gave a boost to firefighters battling two fires at the southern end of Mendocino National Forest, where some 12,200 people were under mandatory evacuation orders.
The Ranch and River fires have charred more than 32,000 hectares, with containment measured at 12% for the two together.
The Carr Fire stood as the most formidable of 94 wildfires burning across 13 US Western states, from Texas to Alaska, according to the National Interagency Fire Center. 
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